Traditionally, computer systems are designed to be able to continuously run a fairly worst-case thermal load corresponding to a worst-case workload. Design according to such a continuous worst-case load has never been much of a problem, because traditionally the individual components have had modest operating power consumptions and the computer systems have had considerable cooling capacity so that the systems could sustain the load fairly naturally.
As the operating power consumptions of the individual components of computer system creep upwards, the thermal budgets of the computer systems have become tighter. The systems have become more difficult to cool. It is now becoming a challenge to design a computer system to run continuously the worst-case thermal load while pursuing other high performance goals, such as high computing power, compactness, quietness, better battery performance, etc.
For example, the systems may no longer be capable of continuously running worst-case workloads naturally without key parts of the system getting too hot.
For example, portable computer systems, such as laptop computers, have a compact housing and limited cooling capability; and thus a worst-case thermal load for a given cooling capability may limit the performance of the system because the worst-case thermal load may rarely occur and yet the system has been designed to sustain the continuous worst-case thermal load. This may mean that the laptop is larger to provide more cooling capability even though the worst-case thermal load may rarely occur.